// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![cfg_attr(not(feature = "std"), no_std)]

extern crate alloc;

// generated file that tells us where to find the fixtures
include!(concat!(env!("OUT_DIR"), "/fixture_location.rs"));

#[cfg(feature = "std")]
pub mod builder;

/// Enum for different fixture types
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FixtureType {
	/// Polkavm (compiled Rust contracts)
	Rust,
	/// Resolc (compiled Solidity contracts to Polkavm)
	Resolc,
	/// Solc (compiled Solidity contracts to EVM bytecode)
	Solc,
	/// Solc Runtime (compiled Solidity contracts to EVM runtime bytecode)
	SolcRuntime,
}

#[cfg(feature = "std")]
impl FixtureType {
	fn file_extension(&self) -> &'static str {
		match self {
			Self::Rust => ".polkavm",
			Self::Resolc => ".resolc.polkavm",
			Self::Solc => ".sol.bin",
			Self::SolcRuntime => ".sol.runtime.bin",
		}
	}
}

/// Load a fixture module with the specified type and return binary contents along with its hash.
#[cfg(feature = "std")]
pub fn compile_module_with_type(
	fixture_name: &str,
	fixture_type: FixtureType,
) -> anyhow::Result<(Vec<u8>, sp_core::H256)> {
	use anyhow::Context;
	let out_dir: std::path::PathBuf = FIXTURE_DIR.into();
	let fixture_path = out_dir.join(format!("{fixture_name}{}", fixture_type.file_extension()));
	let binary = std::fs::read(&fixture_path)
		.with_context(|| format!("Failed to load fixture {fixture_path:?}"))?;
	let code_hash = sp_io::hashing::keccak_256(&binary);
	Ok((binary, sp_core::H256(code_hash)))
}

/// Load a given polkavm module and returns a polkavm binary contents along with its hash.
#[cfg(feature = "std")]
pub fn compile_module(fixture_name: &str) -> anyhow::Result<(Vec<u8>, sp_core::H256)> {
	compile_module_with_type(fixture_name, FixtureType::Rust)
}

/// Try to compile a fixture from the contracts_not_buildable directory.
/// This replicates the build process but expects it to fail at the linking stage.
/// Returns Err if compilation/linking fails (which is expected for invalid fixtures).
#[cfg(feature = "std")]
pub fn try_compile_invalid_fixture(fixture_name: &str) -> anyhow::Result<Vec<u8>> {
	use anyhow::bail;
	use std::{fs, path::PathBuf};

	let manifest_dir = env!("CARGO_MANIFEST_DIR");
	let fixture_path = PathBuf::from(manifest_dir)
		.join("contracts_not_buildable")
		.join(format!("{}.rs", fixture_name));

	if !fixture_path.exists() {
		bail!("Invalid fixture not found: {:?}", fixture_path);
	}

	// Create temporary build directory
	let temp_dir = std::env::temp_dir().join(format!("revive_invalid_fixture_{}", fixture_name));
	fs::create_dir_all(&temp_dir)?;

	// Use the shared builder module to compile
	let result = builder::compile_rust_to_polkavm(&fixture_path, fixture_name, &temp_dir);

	// Cleanup
	let _ = fs::remove_dir_all(&temp_dir);

	result
}

/// Fixtures used in runtime benchmarks.
///
/// We explicitly include those fixtures into the binary to make them
/// available in no-std environments (runtime benchmarks).
pub mod bench {
	use alloc::vec::Vec;
	pub const DUMMY: Option<&[u8]> = fixture!("dummy");
	pub const NOOP: Option<&[u8]> = fixture!("noop");

	pub fn dummy() -> &'static [u8] {
		DUMMY.expect("`DUMMY` fixture not available, remove `SKIP_PALLET_REVIVE_FIXTURES` env variable to compile them.")
	}

	pub fn noop() -> &'static [u8] {
		NOOP.expect("`NOOP` fixture not available, remove `SKIP_PALLET_REVIVE_FIXTURES` env variable to compile them.")
	}

	pub fn dummy_unique(replace_with: u32) -> Vec<u8> {
		let mut dummy = dummy().to_vec();
		let idx = dummy
			.windows(4)
			.position(|w| w == &[0xDE, 0xAD, 0xBE, 0xEF])
			.expect("Benchmark fixture contains this pattern; qed");
		dummy[idx..idx + 4].copy_from_slice(&replace_with.to_le_bytes());
		dummy
	}
}

#[cfg(test)]
mod test {
	#[test]
	fn out_dir_should_have_compiled_mocks() {
		let out_dir: std::path::PathBuf = crate::FIXTURE_DIR.into();
		assert!(out_dir.join("dummy.polkavm").exists());
	}
}
